Optical See-Through Display Luminance Control via Wavelength Diffraction Compensation
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Solution Overview
Problem
Optical see-through display apparatuses face challenges in accurately controlling luminance due to wavelength selectivity of the combiner, which affects diffraction efficiency and results in unintended changes in luminance when the light emission wavelength is altered.
Innovation Solution
A display apparatus and method that control the light output of the light source based on the wavelength of the light emitted and the diffraction efficiency of the combiner, dynamically switching from PWM control to current value control to maintain accurate luminance control, and incorporating feedback and ambient light intensity adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light emission wavelength of the light source is changed to control luminance, then luminance control is achieved, but the diffraction efficiency of the combiner changes unintentionally affecting luminance accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the actual luminance output and the wavelength of light emitted, then adjusts the light source output based on this feedback. The controller is configured to control light emission by considering both the wavelength of light outputted from the light source and the diffraction efficiency of the combiner, creating a closed-loop system that compensates for wavelength-dependent diffraction efficiency variations to achieve accurate luminance control.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the light emission wavelength and light output power based on the required luminance level. The controller modifies operating parameters (wavelength and power) of the light source while compensating for the corresponding changes in diffraction efficiency, enabling accurate luminance control across different brightness levels by changing operational parameters rather than using a fixed wavelength.
2Illumination intensity
If PWM control is used for luminance control, then simple control is achieved, but the dynamic range of luminance is limited
Solution Approach 1:
The patent employs dynamics by transitioning from static PWM control to a dynamic control system that continuously adjusts the light emission wavelength based on the target luminance level. The controller dynamically selects optimal wavelengths and corresponding power levels, enabling extended dynamic range of luminance control. This dynamic approach allows the system to adapt its operating parameters in real-time rather than relying solely on pulse width modulation.
Solution Approach 2:
The patent extends the dynamic range by changing the operating wavelength of the light source in addition to power control. The controller is configured to select different wavelengths corresponding to different luminance ranges, thereby expanding the controllable luminance dynamic range beyond what single-wavelength PWM control can achieve. This multi-parameter control (wavelength + power) provides a broader luminance dynamic range.
3Illumination intensity
If the light source power is increased to compensate for low diffraction efficiency, then luminance is maintained, but energy consumption increases
Solution Approach 1:
The patent optimizes energy efficiency by changing the operating wavelength parameter of the light source to match the diffraction efficiency characteristics of the combiner. Instead of increasing power to compensate for low diffraction efficiency, the controller selects wavelengths where the combiner has higher diffraction efficiency, thereby maintaining required luminance with lower power consumption. This parameter optimization aligns the light source wavelength with the combiner's optimal transmission characteristics.
Solution Approach 2:
The feedback mechanism enables the controller to monitor the relationship between light source wavelength, combiner diffraction efficiency, and actual luminance output. Based on this feedback, the controller adjusts the light source operating parameters to operate at optimal efficiency points, avoiding excessive power consumption. The system learns and adapts to the combiner's wavelength-dependent efficiency characteristics, minimizing energy waste.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise luminance control, expanding the dynamic range of luminance and ensuring accurate display luminance across varying light conditions, enhancing the performance of optical see-through display systems.
Implementation Method 1
a combiner including a diffraction member that diffracts light incident from the light source and outputs the light
Data Source
AI summary
A display apparatus includes an optical see-through display apparatus, and includes a light source that emits lights a combiner including a diffraction member that diffracts light incident from the light source and outputs the light, and a controller that controls light emission of the light source. The controller controls a light output of the light source on the basis of a wavelength of light outputted from the light source and diffraction efficiency of the combiner that is changed resulting from change in a wavelength of incident light.